With reference to FIG. 6, a conventional seam swab is shown and has a rod 51 for the user to hold to control the movement of the swab, a cover 52 pivotally connected to a distal end of the rod 51, two clamps 53 respectively and pivotally connected to opposite sides of the cover 52 and a fabric 54 attached to a bottom of the cover 52 to be clamped by the two clamps 53.
When this type of conventional swab is in use, it is noted that the fabric 54 is clamped by the two clamps 53 at two opposite sides. There is no support to prevent the central portion of the fabric 54 to detach from the bottom of the cover 52 such that the central portion of the fabric 54 is easily detached from the bottom of the cover 52 while two opposite sides of the fabric 54 are still clamped by the two clamps 53. Therefore, when the conventional swab in FIG. 6 is in use, the user will have to be careful of a sudden detachment of the fabric 54 from the cover 52.
To overcome the shortcomings, the present invention intends to provide an improved retaining device to mitigate or obviate the aforementioned problems.